Immunohistochemical distribution of C-reactive protein in the hepatic tissue in forensic autopsy

Previously, we examined the expression of C-reactive protein (CRP) in hepatic tissues in fatal injuries (injury deaths) immunohistochemically, and classified the CRP distribution into three patterns: diffuse (D-) pattern, diffuse with strong positivity in the hepatic lobules; periportal (PP-) pattern, characterized by positive cells in the periportal region of some lobules; focal (F-) pattern, showing small islands of positive cells in some lobules. There was a relationship between the CRP distribution and the survival time. In this study, we further analyzed the deaths including those due to other than fatal injuries (non-injury deaths), and a study of a total of 314 deaths from various causes was performed. Generally, non-injury deaths showed findings similar to those in injury deaths. PP- and/or F-patterns were observed in 43.7% of cases having a short survival time (<6 h), but found in only 3% of those surviving longer (>6 h), showing that such findings are suggestive of a short survival time. D-pattern was found more frequently in non-acute deaths (60.4%), than in acute deaths (10.9%). In acute deaths, D-pattern was found in some cases showing extensive tissue injuries, such as burns and polytrauma, and inflammative predisposition. Immunohistochemical findings also showed some correlation with the serum CRP level. Our data suggest that hepatic CRP immunohistochemistry may be a useful tool for elucidating the dying process.